Mechanical or hydraulically-driven two-cylinder piston pump for conveying concrete, has annular elements axially limiting annular gap under formation of annular space that is filled with liquid, where liquid is pressurized by material

摘要

The pump has an axially movable conveying piston (21) centrally arranged in a conveying cylinder (10) with radial clearance under formation of an annular gap. The piston is connected with a drive cylinder (20) and a drive piston (24) by a piston rod (22) at its rear side that is turned away from a material to be conveyed. Material-sided and rear annular elements respectively form a scraper ring and a pressure seal and axially limit the annular gap under formation of an annular space that is filled with liquid e.g. water or waste oil, where the liquid is pressurized by the material. The pressure seal is formed as an annular mantle seal.